This invention relates to teaching and more particularly to aids for teaching.
Learning, especially at the lower grade levels, is through the repetitive performance of a task such as spelling, mathematics, geography, etc. The student is taught how the task is performed by observing the instructor perform the same or similar task and thereafter attempting the task themselves.
Traditionally, this teaching is accomplished via a blackboard or other such display on a wall. The instructor prints a problem and explains the steps of the solution. The students are supplied with paper worksheets that have similar problems.
Although the paper worksheets are inexpensive to print, for young students many mistakes are made before the task is correctly performed. These mistakes must be erased; on paper this causes rips, tears, and smudges which inhibits the student in the learning process.
The blackboard itself creates problems. Whereas, the traditional classroom had the entire classroom working on the same problem; the modern classroom recognizes that students are individuals and perform their tasks and learn new ones at varying speeds. In the modern classroom, many subjects permit the student to "self-pace" or learn the subject at a speed with which the student feels comfortable.
This improved approach to teaching means that the instructor is faced with the situation that multiple lessons are being performed simultaneously within the class. Explaining a particular task on the blackboard is not only cumbersome but is disruptive. Students who are either behind the task being performed or ahead of it find the black-board work confusing and interruptive.
Recognizing that it is desirable to be able to use the worksheet itself as a visual reference, several devices have been made permitting the worksheet to be secured under a clear plate. By writing on the clear plate, the worksheet can be repeatedly completed without actually marking on the worksheet.
One such device is described in U.S. Pat. No. 1,757,287, entitled "Perpetual Pad" issued May 6, 1930, to Bildstein. In the Bildstein device, the worksheet is mechanically squeezed between two plates and locked into position. This arrangement requires the use of heavy materials and hinges. The plates, when opened and shut, are disruptive in the classroom and are difficult for small children to utilize.
To reduce the weight and complexity of these types of devices, a group of binders were developed which mechanically clasp the worksheets along one edge. Such devices are described in: U.S. Pat. No. 3,553,864, entitled "Map Holder" issued Jan. 12, 1971, to Karlyn et. al; U.S. Pat. No. 2,791,040, entitled "Map Folio" issued May 7, 1957, to Santorelli; U.S. Pat. No. 3,092,400, entitled "Loose Leaf Binder" issued June 4, 1963, to Smith; and, U.S. Pat. No. 3,252,462, entitled "Binder for Magazines and the Like" issued May 24, 1966, to Quarton et. al.
In all of these devices, the worksheet or map is clasped along one edge. Removing the worksheet is difficult and cumbersome in a classroom situation.
Another attempted solution to the problem is to place the paper worksheet between two flexible sheets of clear plastic. The sheets sandwich the paper worksheet therebetween. This secures the worksheet in place permitting the student/user to work out the problem without marking the paper.
This type of arrangement is described in U.S. Pat. No. 3,206,225, entitled "Self-Hinging Laminated Plastic Folders" issued Sept. 14, 1965, to Oleson; and, U.S. Pat. No. 2,608,771, entitled "Writing Pad" issued Sept. 2, 1952, to Sparks.
Although this approach does provide ease in use, the flexible plastic is not conducive to repeated writing and erasure. Repeated use smudges the thin plastic.
Additionally, the ink from the underlying paper is transferred to the plastic. This creates smudges on the plastic, diminishing the transparency of the plastic.
It is clear from the foregoing that an effective solution does not exist.